Vibration test method and simulation device

Abstract

To provide a method for running a vibration test which can re-create vibrations in a process of transferring a storage body and can be easily executed.SOLUTION: The method for running a vibration test according to the present invention includes a simulation step and an application step of applying a vibration on a storage body 12 storing a plurality of items 11 by using a vibration test device 30. The simulation step is a step of deriving a vibration condition of the vibration test device 30 by a simulation on the basis of accumulated fatigue. The application step is a step of applying a vibration on the storage body 12 under the vibration condition by using the vibration test device 30. The accumulated fatigue is calculated on the basis of a relative acceleration as the difference of acceleration among a plurality of measurement targets 10a and 10b in the storage body 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vibration testing method. [Background technology]

[0002] In the distribution process of goods and the like, the container in which the goods are stored may be subjected to vibration, which may cause deformation or damage to the goods. Vibration testing is known in which such vibration is reproduced to evaluate the presence or absence of deformation or damage to the goods. For example, Patent Document 1 discloses a vibration testing method that includes a step of calculating the accumulated fatigue occurring in the transported goods under the transport conditions in actual transportation as theoretical accumulated fatigue, and a step of vibrating the transported goods for a predetermined period of time at the vibration acceleration under the transport conditions through a vibration test using a vibration table, and calculating the accumulated fatigue as actual fatigue from the vibration acceleration occurring in the transported goods, and repeating the vibration test with increasing the vibration acceleration of the vibration table until the actual fatigue becomes equal to the theoretical accumulated fatigue.

[0003] Furthermore, the JIS specifies test methods for evaluating the durability of the contents or packaging of transported goods against vertical vibrations that the transported goods are subjected to during transportation (Non-Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-181195 A [Non-Patent Document 1] JIS Z 0200_2013 General rules for performance test methods for packaged goods [Non-Patent Document 2] JIS Z 0232_2004 Packaged cargo-Vibration test method Summary of the Invention [Problem to be solved by the invention]

[0005] From the viewpoint of grasping the durability of products and packages against vibration, it is required that the vibration test can reproduce vibration suitable for the actual transportation conditions. Although the vibration test methods of Patent Document 1 and Non-Patent Documents 1 and 2 reproduce the vibration of a transportation means such as a vehicle that generates vibration, the degree of damage to products caused by the vibration of the vibration test method is different from the degree of damage to products caused on the actual transportation route. In particular, it is difficult to reproduce the degree of damage to products stored in a container by the conventional vibration test. In addition, in order to reproduce the vibration of a transportation means, it is necessary to grasp the behavior of the vibration in the transportation state using the actual transportation means in advance, and it is difficult to perform a vibration test simply.

[0006] Therefore, the present invention provides a vibration test method that is highly reproducible and easy to use during transportation of a package. [Means for solving the problem]

[0007] The present invention relates to a vibration testing method. In one embodiment, the vibration testing method preferably includes a simulation step and a vibration application step of applying vibration to a container in which a plurality of items are contained, using a vibration testing device. The simulation step is a step of deriving vibration conditions for the vibration testing device through simulation based on accumulated fatigue. The vibration applying step is a step of applying vibration to the housing under the vibration conditions using the vibration test device. The accumulated fatigue is calculated based on a relative acceleration, which is a difference in acceleration between a plurality of measurement objects in the container. Effect of the Invention

[0008] According to the vibration test method of the present invention, the vibration occurring during the transportation of the package can be easily and reproducibly carried out. [Brief description of the drawings]

[0009] [Figure 1]FIG. 1 is a schematic explanatory diagram showing an embodiment of a vibration testing method according to the present invention. [Diagram 2] FIG. 2 is a plan view of a container according to the present invention. [Diagram 3] FIG. 3 is a graph showing an example of a change in relative acceleration over time. [Figure 4] FIG. 4 is a perspective view for explaining the articles in the container in the vibration applying step. [Diagram 5] FIG. 5 is a flow diagram of the vibration test method shown in FIG. [Figure 6] FIG. 6 is a schematic explanatory diagram showing another embodiment of a vibration testing method according to the present invention. [Figure 7] FIG. 7 is a graph showing the frequency distribution of acceleration in vibration test evaluation I of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will now be described based on preferred embodiments with reference to the drawings. The vibration test method of this embodiment includes a preliminary step of measuring the relative acceleration of a container 12 containing a plurality of items 11 in a transport state, a simulation step, and a vibration application step of applying vibration to the container 12 using a vibration test device (see FIG. 1). Details of the relative acceleration will be described later. In the simulation step, the vibration conditions of the vibration test device are simulated, and in the vibration application step, the actual container 12 is actually vibrated according to the vibration conditions obtained in the simulation step to perform a vibration test.

[0011] The container 12, which is the simulation target and vibration target of the vibration testing method of this embodiment, has an internal storage space for storing a plurality of items 11. The container 12 may be a packaging material that reflects the transportation conditions, such as a cardboard box, a wooden box, a plastic container, etc. From the viewpoint of versatility, it is preferable to use a cardboard box 17 as the container 12 (see Figs. 1 and 2).

[0012] The article 11 may be anything depending on the purpose of the vibration test. For example, the article 11 may be a product that is transported (distributed) while being housed in a container 12, or a prototype in the development stage. The container 12 of this embodiment is a cardboard box 17, and the items 11 contained in the container 12 are packaging containers 16 filled with detergent (see FIG. 1). The container 12 has a longitudinal direction X, a width direction Y perpendicular to the longitudinal direction X, and a height direction Z along the vertical direction (see FIG. 4), and four rows of three packaging containers 16 lined up in the width direction Y are lined up along the longitudinal direction X. That is, the container 12 of this embodiment contains twelve packaging containers 16.

[0013] In each of the preliminary step and the simulation step of this embodiment, a plurality of measurement targets 10a, 10b are set for a container 12 that contains a plurality of items 11. The plurality of measurement targets 10a, 10b may be the items 11, may include the items 11 and the container 12, or may be only the container 12. When the measurement objects 10a and 10b include articles 11, the measurement objects 10a and 10b are selected from the multiple articles 11 in the container 12. When the measurement objects 10a and 10b are the same articles 11, multiple different articles 11 are selected in the container 12 and are set as the measurement objects 10a and 10b. When the measurement objects include the container 12, the measurement objects 10a and 10b are selected from the inner wall of the container 12, i.e., the portion of the container 12 facing the article 11. For example, a portion of the peripheral wall rising from the bottom surface of the container 12 is selected as the measurement object. The number of objects to be measured can be two or more, and may be three or more.

[0014] The vibration test method of this embodiment includes a preliminary step prior to the simulation step. In the preliminary step, the acceleration between the multiple measurement objects 10a, 10b in the housing 12 is measured, and the relative acceleration, which is the difference between these accelerations, is measured. From the viewpoint of further improving the reproducibility of damage caused by vibration, the acceleration between the multiple measurement objects 10a, 10b for calculating the relative acceleration is preferably the vertical acceleration. In the vibration test method of this embodiment, the difference (G1-G2) between the vertical acceleration (G1) measured by the first acceleration sensor A1 and the vertical acceleration (G2) measured by the second acceleration sensor A2 is defined as the relative acceleration. The relative acceleration between the multiple measurement objects 10a, 10b in the housing 12 is hereinafter also referred to simply as the "relative acceleration."

[0015] In the preliminary step, the acceleration between the multiple measurement objects 10a, 10b in the transported state is measured, and the relative acceleration, which is the difference between these accelerations, is measured. In this preliminary step, the change over time in the relative acceleration while the container 12 is being transported is measured. That is, the acceleration difference (relative acceleration) between the measurement objects 10a, 10b in the container 12 transported by a transport means 18 such as a vehicle is continuously measured (see FIG. 1). The change in relative acceleration over time measured in the preliminary step may be measured for the entire section of the transportation route from the starting point to the destination, or may be measured for only a portion of the transportation route. In the latter case, the change in relative acceleration over time for the entire transportation route may be predicted from the change in relative acceleration over time for the portion of the transportation route, and the predicted value may be used as the change in relative acceleration over time obtained in the preliminary step.

[0016] The transportation means 18 for transporting the container 12 in the preliminary process is not particularly limited, and can be any one of land transportation using vehicles or railways, sea transportation using ships or the like, and aerial transportation using aircraft or drones or the like, or a combination of these transportation methods. In the present embodiment, the transportation state in the preliminary process is a state in which the product is transported by land.

[0017] In the preliminary process of this embodiment, for one of the multiple packages 12 loaded on the platform of the transport means 18, a first acceleration sensor A1 is attached to a packaging container 16a inside the package 12, and a second acceleration sensor A2 is attached to another packaging container 16b inside the package 12, and the relative accelerations thereof are measured (see FIG. 2). In the preliminary process of this embodiment, the acceleration sensors A1 and A2 output and record, by wire or wireless, one or both of acceleration data and relative acceleration data to a recorder (not shown) during transportation. In this way, in the preliminary process of this embodiment, by continuously measuring the relative acceleration during transportation, a graph of the change over time in the relative acceleration during transportation can be obtained (see FIG. 1).

[0018] In the preliminary step of this embodiment, the two packaging containers 16a, 16b in the container 12 are the measurement objects 10a, 10b (see Figs. 1 and 2). The acceleration sensors A1, A2 can be any sensor capable of continuously measuring acceleration without any particular restrictions. These acceleration sensors A1, A2 measure acceleration in three directions, the XYZ axes (horizontal and vertical directions). In this embodiment, these acceleration sensors A1 and A2 are hereinafter also referred to as the "first acceleration sensor A1" and the "second acceleration sensor A2." The first acceleration sensor A1 is attached to one packaging container 16a, and the second acceleration sensor A2 is attached to a packaging container 16b other than the packaging container 16a to which the first acceleration sensor A1 is attached.

[0019] It is preferable to carry out the preliminary process under different transport conditions and accumulate information such as relative acceleration corresponding to each transport condition as corresponding information. Examples of the corresponding information include information on the measurement objects 10a and 10b, the relative acceleration of the measurement objects 10a and 10b, accumulated fatigue based on the relative acceleration, profile information such as power spectrum density, and information on the transport route. The information on the transport route includes information on the departure point, destination, mileage, type of vehicle, loading position on the loading platform, road surface condition, etc. In the vibration test method of this embodiment, the corresponding information is stored in a simulation device 19, which will be described later. Among the corresponding information, profile information is stored as a relative acceleration condition, which will be described later. This enables an analysis that correlates the degree and number of damages caused by vibrations in a vibration application process, which will be described later, with the transportation conditions.

[0020] The simulation step performed after the preliminary step is a step of modeling the housing 12 to be vibrated in the vibration step, and deriving vibration conditions of the vibration test device 30 by simulation based on the target accumulated fatigue. The simulation step of this embodiment derives vibration conditions equivalent to the accumulated fatigue based on the relative acceleration measured in the preliminary step. The details of such derivation will be described later. The simulation step is executed by a simulation device 19 (see FIG. 1). Known analysis software is installed in the simulation device 19, and the behavior of vibration in the housing body 12 can be simulated using the simulation software.

[0021] From the viewpoint of more reliably reproducible damage caused by vibration, the simulation step models the mass, hardness, restitution coefficient or damping coefficient, vibration frequency, etc. of the container 12 to be vibrated in the vibration step and the article contained therein. From the viewpoint of more reproducing the storage state of the article 11 in the internal space of the container 12, it is preferable to model using three-dimensional data of the article 11 and the container 12. The three-dimensional data can be created by three-dimensional CAD (Computer-Aided Design). In the simulation step of this embodiment, two different packaging containers 16a, 16b in the modeled container 12 are used as measurement objects. From the viewpoint of reproducibility of damage caused by vibration more reliably, it is preferable that the measurement objects 10a, 10b in the housing 12 are common to the preliminary step and the simulation step. That is, in the simulation step, it is preferable to select as the measurement object for the modeled housing 12 the same object to which the acceleration sensors A1, A2 are attached in the preliminary step (see FIG. 2). Note that although the acceleration sensors A1, A2 are shown in FIGS. 1, 2, and 4, the sensors are excluded from the modeling and simulation performed in the simulation step.

[0022] The simulation step simulates the behavior of the vibration table 35 of the vibration test device 30 used in the vibration excitation step. The behavior of the vibration table 35 is an element that indicates the movement of the vibration table 35 when the setting conditions (waveform, frequency) of the vibration test device 30 are changed, and is the movement direction (acceleration direction) and movement amount (acceleration) of the vibration table 35. From the viewpoint of more reliably obtaining the above-mentioned reproducibility, the simulation step preferably simulates the movement of the vibration table 35 in the same direction as the acceleration direction measured in the preliminary step. It is more preferable to simulate the vertical movement (phase) of the vibration table 35. In such a simulation, information required for modeling the vibration table 35 (mass, hardness, restitution coefficient or damping coefficient, vibration frequency, etc. of the vibration table 35) is input in advance to the simulation device 19. In this way, the vibration table 35 is modeled.

[0023] In the simulation step, the relative acceleration of the measurement objects 10a and 10b is continuously calculated when the housing 12 is vibrated by the vibration test device 30 with different set conditions. That is, a graph of the change over time of the relative acceleration when the modeled housing 12 is vibrated with different set conditions can be obtained (see FIG. 1). This makes it possible to simulate the change over time of the relative acceleration of the measurement objects 10a and 10b when the housing 12 is vibrated by the vibration test device 30 used in the vibration excitation step.

[0024] The derivation of vibration conditions in the simulation process will be described in detail. This derivation is performed based on the desired accumulated fatigue. In this embodiment, vibration conditions equivalent to the accumulated fatigue based on the change over time of the relative acceleration calculated by the simulation are derived. The accumulated fatigue is based on the S-N curve and is calculated by the following formula (1).

[0025]

number

[0026] In the above formula (1), "β" is "accumulated fatigue" and is calculated from a graph (waveform) showing the change over time in relative acceleration. The graph is a waveform in which the relative acceleration alternates between positive and negative peaks, centered around the zero axis. In the above formula (1), each peak in this waveform is "i", and the relative acceleration of each peak is "G1-G2". Also, in the above formula (1), "α" is the "acceleration coefficient". In other words, the accumulated fatigue (β) calculated by the above formula (1) is the value (|g i | α ) is the sum of all the For example, in the graph shown in Figure 3, the sum of the absolute values ​​of the peak values ​​in the 12 vibrations (frequencies) raised to the power of α (|g1| α +|g2| α +|g3| α +····+|g 11 | α +|g 12 | α ) is the accumulated fatigue of relative acceleration.

[0027] The "α" is the slope of the S-N curve of the measurement objects 10a and 10b, and is a value specific to the measurement object. The larger the value of "α", the higher the sensitivity of damage to acceleration. When the materials of the multiple measurement objects 10a, 10b are different, for example when the measurement objects are the container 12 and the item 11 (packaging container 16 in this embodiment), "α" is a value specific to the measurement object being evaluated for damage due to vibration.

[0028] The simulation process sets a certain accumulated fatigue as a target value, and derives vibration conditions under which the accumulated fatigue when the housing 12 is vibrated by the vibration test device 30 is equivalent to the target value. In the simulation process of this embodiment, the accumulated fatigue based on the relative acceleration between the measurement objects 10a, 10b measured in the preliminary process is set as the target value. The accumulated fatigue set as the target value is hereinafter also referred to as "target accumulated fatigue." That is, in this embodiment, the accumulated fatigue measured in the preliminary process is set as the target accumulated fatigue, and the simulation process derives vibration conditions under which the accumulated fatigue of the vibration by the vibration test device 30 is equivalent to the target accumulated fatigue.

[0029] The simulation process of this embodiment simulates the case where the housing 12 is vibrated at a certain frequency and acceleration using the vibration test device 30, and calculates the relative acceleration between the measurement objects 10a, 10b per unit time and the accumulated fatigue based on the relative acceleration per unit time. That is, the accumulated fatigue per unit time of vibration by the vibration test device 30 is calculated. Then, from this accumulated fatigue per unit time, a vibration time equivalent to the target accumulated fatigue applied to the measurement objects 10a, 10b when the vibration test device 30 is operated under the above-mentioned frequency and acceleration conditions is calculated. In this way, the simulation process of this embodiment derives vibration conditions (frequency, acceleration, and vibration time) that can apply a load equivalent to the target accumulated fatigue to the measurement objects 10a, 10b.

[0030] In the simulation step, one or more of the vibration frequency, vibration time, acceleration, and the waveform of the acceleration may be set as the vibration conditions for the vibration test device 30, but it is preferable to determine the combination of the vibration frequency and the acceleration range manually, calculate the relative acceleration per unit time between the measurement objects 10a, 10b and the accumulated fatigue based on the relative acceleration per unit time, and derive the vibration conditions. The combination of the vibration frequency and the acceleration range is input to the simulation device 19, for example, according to the operation of the operator. In this operation, the operator can set the waveform of the vibration test device 30 to be simulated, such as a sine wave, and can also set the frequency and acceleration range.

[0031] From the viewpoint of more efficiently performing dynamic analysis of the measurement objects 10a, 10 in the housing 12 due to vibration, it is preferable to perform the simulation of the simulation step by multibody dynamics. Multibody dynamics is an analysis method for dynamically analyzing elements in a system consisting of multiple elements (measurement objects 10a, 10b, etc.) that interact with each other, and for example, the degree of freedom (constraint conditions) for the movement of the elements, the masses, moments of inertia, and center of gravity positions of the elements are appropriately set. For the simulation by multibody dynamics, commercially available analysis software such as MotionSolve in Hyper Works manufactured by Altair Corporation can be used. In the simulation process of this embodiment, the displacements on the xyz coordinates of the measurement objects 10a and 10b in the container 12 shown in FIGS. 1, 2, and 4, that is, the packaging containers 16a and 16b, are analyzed by multibody dynamics.

[0032] In the simulation step of this embodiment, an operator performs a simulation by inputting information required for a multibody dynamics simulation into the simulation device 19. In the simulation step of this embodiment, the operator inputs the three-dimensional shape, mass, hardness, restitution coefficient or damping coefficient, vibration frequency, etc. of the container 12 and the item 11 contained therein into the simulation device 19 as information required for the simulation. In the simulation step of this embodiment, information required for the simulation is read and a simulation result is output. As the simulation result, the change over time of the relative acceleration of the measurement objects 10a and 10b, the change over time of the motion (displacement, speed, acceleration, attitude, angular velocity) of the container 12 and the object 11 including the measurement objects 10a and 10b, the load and torque that the container 12 or the object 11 receives due to vibration, etc. are output. The change over time of the motion may be output as numerical values ​​such as the change in displacement, speed, acceleration, attitude, and angular velocity of the container 12 and the object 11 related to the motion, and the change in the load and torque that the container 12 or the object 11 receives due to vibration, but may also be a video in which simulation images (see FIG. 1) of the inside of the container 12 corresponding to the vibration time are continuously displayed over time.

[0033] The vibration application step is a step of applying vibration to the housing 12 using a vibration test device 30 under the vibration conditions derived in the simulation step. The vibration excitation step in this embodiment is a step of setting the vibration test device 30 to the vibration conditions described above and vibrating the housing 12. In the vibration excitation step, the vibration conditions derived by the simulation device 19 are sent to the control device of the vibration test device 30, or the settings of the vibration test device 30 are manually set to the vibration conditions. Then, the vibration test device 30 is operated under the vibration conditions, and vibration is applied to the housing 12 placed on the vibration table 35. This makes it possible to apply vibration to the measurement objects 10a, 10b with accumulated fatigue equivalent to the target accumulated fatigue.

[0034] The vibration test device 30 used in the vibration excitation step of this embodiment includes a vibration table 35 on which an object to be excited is placed, and a vibration generating unit 31 that vibrates the vibration table 35 (see FIG. 1). The vibration test device 30 may be any known vibration test device, such as a mechanical type, an electrodynamic type, or a hydraulic type.

[0035] The simulation device 19 described above includes a CPU, a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, a camera, a display unit, an input device for a user to perform input operations, and the like. The CPU may include a graphics processor (Graphics Processing Unit (GPU)) for displaying images, a multimedia processor for encoding and decoding High-Definition (HD) video and the like, a display controller for controlling the display, and a power management Integrated Circuit (IC) for controlling power supply and charging. The display unit of the simulation device 19 may be a touch panel or the like having both display and operation functions. Examples of the input device include a touch panel, a keyboard, a keypad, a touchpad, a mouse, a microphone, and the like. An operator of the simulation device 19 uses an input device to operate the simulation device 19. The processing performed by the simulation device 19 is realized by a CPU expanding a program stored in a ROM, a disk, etc., into a RAM and executing the program. The processing may be realized by an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array), or may be realized by a combination of an ASIC and an FPGA.

[0036] Furthermore, when the operation of the vibration testing equipment 30 is controlled by a control device, the control device can have the same configuration as the simulation equipment 19. In this case, the simulation equipment 19 and the control device are connected via a network, and transmit and receive data such as vibration conditions between them. A network refers to any information and communication network that utilizes telecommunications technology, including wireless or wired LANs (Local Area Networks) such as LANs, the Internet, telephone communication lines, optical fiber communication networks, cable communication networks, and satellite communication networks.

[0037] In the vibration process of this embodiment, vibration is applied to the housing 12 so that the accumulated fatigue is equivalent to the accumulated fatigue (target accumulated fatigue) based on the relative acceleration measured in the preliminary process. In other words, the housing 12 placed on the vibration table 35 is vibrated, and the vibration test device 30 is operated under vibration conditions under which the accumulated fatigue based on the relative acceleration in the vibration process (hereinafter also referred to as "test accumulated fatigue") is equivalent to the target accumulated fatigue. The test accumulated fatigue is accumulated fatigue based on the relative acceleration between the housing 12, which is the vibration target in the vibration process, and the objects corresponding to the multiple measurement objects 10a and 10b in the simulation process (hereinafter also referred to as "test objects"). Based on the S-N curve, theoretically, even if the vibration conditions (vibration behavior) are different, if the accumulated fatigue is equivalent, the same degree of damage will occur. Based on this theory, if the housing 12 is vibrated under vibration conditions equivalent to the target accumulated fatigue calculated in the simulation process, the test accumulated fatigue can be made equivalent to the target accumulated fatigue. That is, in the vibration application process, a load equivalent to the target accumulated fatigue can be applied to the items corresponding to the multiple measurement objects 10a, 10b in the housing 12. Also, based on the above theory, it is not necessary to measure the accumulated fatigue during the test in real time. In this way, the vibration application process of this embodiment allows the vibration test to be performed very simply by setting the vibration conditions.

[0038] As described above, the vibration test method of this embodiment applies vibration to the housing 12 based on the accumulated fatigue in the housing 12. This accumulated fatigue is based on the relative acceleration reflecting the displacement difference between the measurement objects 10a, 10b such as a part of the housing 12 and the item 11, and is an index reflecting a collision between the housing 12 and the item 11 or a collision between the items 11 (see FIG. 4) that may occur in the housing 12 due to vibration, so that damage caused by vibration in the housing 12 can be reproduced with high reproducibility. On the other hand, the conventional vibration test method reproduces the vibration behavior of the vibration source (e.g., the loading platform of a means of transportation, etc.), so that it is difficult to reflect the vibration behavior occurring in the housing 12, and the reproduction of damage that may occur due to actual vibration is low. The specific effect of the reproducibility of the vibration application process based on the accumulated fatigue will be shown in the examples described later. In addition, in conventional vibration testing methods, the phase shift of each measurement object varies, which causes damage to vary depending on the frequency. In contrast, in the vibration process of this embodiment, the accumulated fatigue is based on the relative acceleration, which reduces the variation in the phase shift between the measurement objects, thereby suppressing the effect of frequency. Furthermore, by setting the target accumulated fatigue as a target value, it is possible to easily set the frequency and duration of the vibration applied to the housing 12. This makes it easier to narrow down the frequency of the vibration to a specific range, and also makes it possible to shorten the duration of the vibration, enabling efficient vibration testing.

[0039] After the vibration step, the accommodation body 12 to be vibrated has a load equivalent to the target accumulated fatigue applied to the test objects corresponding to the measurement objects 10a, 10b in the preliminary step and the simulation step. By checking the presence or absence of damage to the test objects and the degree of damage, it is possible to reproduce damage caused by vibration occurring within the accommodation body 12. In the vibration testing method of this embodiment, the accumulated fatigue measured in the preliminary step is the target accumulated fatigue, so that damage caused by vibration during transportation can be reproduced with high reproducibility.

[0040] The vibration testing method of this embodiment can determine the vibration conditions of the vibration testing device 30 for making the accumulated fatigue during the test equivalent to the target accumulated fatigue, i.e., the vibration conditions corresponding to the target accumulated fatigue, by executing a simulation process. From the viewpoint of performing the vibration test more easily, the vibration test method of this embodiment preferably includes a repeating step in which the same step as the vibration applying step is performed by repeatedly using the vibration conditions. In the repeating step, vibration is applied to another container 12 using the vibration test device 30 under the vibration conditions derived in the simulation step. In this case, the storage state of the container 12 used in the repeating step is set to the same conditions as in the vibration applying step. In the repeating step, vibration is applied under the same vibration conditions as in the vibration applying step, so that a load equivalent to the target accumulated fatigue can be applied to the test object corresponding to the measurement objects 10a, 10b of the container 12 without repeatedly performing the simulation step. In other words, when performing a vibration test on another sample (container 12), only the vibration applying step is required. This allows the vibration test to be performed more efficiently and simply, and in particular, makes it easier to perform a comparative durability test of the packaging material used for the item 11.

[0041] In the vibration test method of this embodiment, the multiple measurement objects 10a, 10b in the container 12 may be arranged in a spaced apart state or adjacent to each other. From the viewpoint of further improving the reproducibility of the collision between the container 12 and the article 11 or the collision between the articles 11 due to vibration, the multiple measurement objects 10a, 10b are preferably the articles 11 accommodated in the container 12 so as to be able to come into contact with each other. In this case, the measurement objects 10a, 10b may be, for example, packaging containers 16a, 16b adjacent to each other in the longitudinal direction X or width direction Y in the container 12 (see Figs. 2 and 4). The multiple measurement objects 10a, 10b may be adjacent to each other via a cushioning material, a partition, or the like.

[0042] From the viewpoint of further improving the reproducibility of damage caused by vibration, it is preferable that the multiple measurement objects 10a, 10b are the items that are most damaged by vibration in the housing 12. In this case, the measurement objects 10a, 10b are the items that were most severely damaged among the items contained in the housing 12 loaded in the actual transportation.

[0043] Next, the flow of the vibration testing method according to the above-mentioned embodiment will be described with reference to FIG. In the vibration test method of this embodiment, a simulation step is performed to derive vibration conditions equivalent to the target accumulated fatigue (step S1). In this derivation, information required for the simulation, such as the mass, hardness, restitution coefficient, or damping coefficient of the vibration table 35, the housing body 12, and the object 11, is input to the simulation device 19 in response to an operation by an operator. In step S1, a simulation is performed in which the modeled housing body 12 is vibrated by the vibration table 35 (vibration test device 30), and the relative acceleration per unit time and the accumulated fatigue based thereon are calculated for the measurement objects 10a and 10b in the housing body 12. Then, vibration conditions of the vibration table 35 (vibration test device 30) equivalent to the target accumulated fatigue are derived. The vibration conditions include conditions of frequency, acceleration, and vibration time. In step S1 of this embodiment, a simulation in which the modeled housing body 12 is vibrated is performed by multibody dynamics.

[0044] In the following step S2, the vibration conditions obtained in step S1 are set in the vibration test device 30. Step S2 may be performed in response to an operation by an operator.

[0045] The next step S3 corresponds to the vibration step described above. In step S3, the housing 12 is placed on the vibration table 35 of the vibration test device 30, and vibration is applied to the housing 12 under the vibration conditions set in step S3. In step S3, the vibration test device 30 set to the vibration conditions is operated. By satisfying such vibration conditions, the accumulated fatigue during the test becomes equivalent to the target accumulated fatigue. When the operation of the vibration test device 30 satisfies the vibration conditions, the process proceeds to step S4, where vibration application by the vibration test device 30 is terminated.

[0046] In the next step S5, it is determined whether or not to perform the repeating process. If it is determined in step S5 that the repeating process is to be performed, the process returns to step S3, and the operations from step S3 onwards are repeated. In this case, another container 12 is placed on the vibration table 35 of the vibration test apparatus 30 in step S3. If it is determined in step S5 that the repeating process is not to be performed, the power supply to the vibration test apparatus 30 is stopped, and the vibration test is terminated. In step S5 of this embodiment, a display is output on the control device of the vibration test apparatus 30 or the display unit of the simulation apparatus 19 connected to the vibration test apparatus 30 via a network, prompting the operator to determine whether or not to perform the repeating process. In response to the display, the operator operates the control device or the input device of the simulation apparatus 19 to determine whether or not to perform the repeating process.

[0047] After the above steps S1 to S5, the container 12 to which the vibration has been applied in the vibration application step is checked for the presence or absence of damage to the test objects corresponding to the measurement objects 10a and 10b and the extent of the damage. Such checking is performed visually. For example, the appearance of the packaging container 16 corresponding to the measurement objects 10a and 10b is visually checked for peeling of the label and the presence or absence of cracks in the packaging container 16. In this manner, the vibration testing method of this embodiment can reproduce damage caused by vibration during the transportation of the container 12.

[0048] The vibration testing method of the present invention is not limited to the embodiment shown in Figs. 1 to 5, and may be another embodiment. Another embodiment of the vibration testing method according to the present invention will be described below. In the description of the other embodiment shown below, components different from the embodiment shown in Figs. 1 to 5 will be mainly described, and similar components will be given the same reference numerals and description will be omitted. For components that are not particularly described, the description of the embodiment shown in Figs. 1 to 5 will be applied as appropriate.

[0049] The vibration testing method shown in FIG. 6 includes a simulation process including a first simulation process for calculating the relative acceleration between multiple measurement objects (not shown in FIG. 6) in a transport state and the accumulated fatigue based thereon, and a second simulation process for deriving vibration conditions. The simulation step of this embodiment is executed by the simulation device 19. Moreover, the second simulation step corresponds to the simulation step of the above-described embodiment.

[0050] The first simulation step is a step of calculating the target accumulated fatigue by simulation. In this step, similar to the embodiment shown in Figs. 1 to 5, the housing 12 is modeled, and a transportation means such as a vehicle 18 that transports the housing 12 and a transportation route are modeled to simulate vibrations applied to a plurality of measurement objects in the housing 12 in a transported state. The first simulation step is performed using known simulation software. The means of transport is modeled by inputting information such as the type, volume, weight, speed, type and output of the power generator (engine) of the means of transport into the simulation device 19. The transport route is modeled by inputting information such as the travel distance and road surface information into the simulation device 19.

[0051] The first simulation step calculates the relative acceleration occurring between the multiple measurement objects in the housing 12 based on the modeled housing 12, transportation means, and transportation route, and further calculates the accumulated fatigue based on the relative acceleration. This makes it possible to obtain the target accumulated fatigue that can occur under the same or similar vibration conditions in the actual transportation state. In other words, since the target accumulated fatigue under the same or similar vibration conditions in the transportation state can be obtained without having to perform an actual transportation test in advance, the vibration test can be performed efficiently in a short time.

[0052] In the second simulation step, vibration conditions equivalent to the target accumulated fatigue calculated in the first simulation step are derived. In the subsequent vibration application step, vibration is applied to the housing 12 using a vibration test device 30 in the same manner as in the above-described embodiment. In the vibration test method of this embodiment, the first simulation step is performed instead of the preliminary step, so that the vibration test can be performed more simply. In addition, the vibration test method of this embodiment can obtain the same effects as the above-mentioned embodiment.

[0053] Although the present invention has been described based on the preferred embodiments, the present invention is not limited to the above-described embodiments. For example, the container 12 in the above-described embodiment is the cardboard box 17 containing a plurality of packaging containers 16, but the container 12 is not limited to this form. The container 12 may contain cushioning material together with the article 11. In the vibration test method of the above embodiment, damage to the appearance of the article 11 (packaging container 16) is checked, but instead, damage to the inside of the article 11 may be checked. For example, if the article 11 is a solid cosmetic such as eye shadow or foundation with a powder cosmetic filled inside a packaging container, damage to the contents of the packaging container (solid cosmetic) may be checked.

[0054] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to such examples.

[0055] [Vibration test evaluation I] The acceleration of the object to be measured in the actual vibration test and in the simulation of the vibration test were compared to evaluate the reproducibility of the acceleration in the simulation.

[0056] Example 1 A simulation process based on multibody dynamics was carried out using the simulation device 19 shown in FIG. 1, and the reproducibility of the acceleration of the measurement object 10a due to vibration using the vibration test device 30 was evaluated. First, in the simulation process, the container 12 shown in FIG. 2 was modeled. The container 12 was modeled as shown in FIG. 2 and FIG. 4. The container 12 was a cardboard box 17, and as shown in FIG. 2, a packaging container 16 consisting of 12 plastic bottles was set to be contained therein. The content volume of the packaging container 16 was 850 mL. The acceleration coefficient α of this packaging container 16 was "2". Three-dimensional data was created using a three-dimensional CAD (Computer-Aided Design) for each of the 12 packaging containers 16 and the cardboard box 17 containing them. In addition, three-dimensional data was also created for the vibration table 35 of the vibration test device 30 used in Reference Example 1 described later. The three-dimensional data is data on the state in which the 12 packaging containers 16 are contained in the container 12. These three-dimensional data, as well as information on the container 12 and the packaging container 16 (content volume, acceleration coefficient α) were input into the simulation device 19 as modeling conditions.

[0057] One measurement object 10a was set for the modeled container 12. The measurement object 10a was a packaging container 16a at the center of the width direction Y, which was one of two rows at the center in the longitudinal direction X, among rows of three packaging containers 16 lined up in the width direction Y, as shown in FIG. Next, the modeled container 12 placed on the modeled vibration table 35 was vibrated with a sine wave (constant displacement, peak-to-peak value (PP value) 1.4 mm) at different frequencies of 20 Hz, 25 Hz, 30 Hz, and 35 Hz to simulate the case, and the frequency distribution of the acceleration of the measurement object 10a was obtained. The vibration time for each condition was 4 seconds. A graph of the frequency distribution is shown in FIG. 7.

[0058] [Reference example 1] A real container 12 having the same configuration as that shown in FIG. 2 was prepared, and a vibration test was performed by vibrating the container 12. In the container 12, an acceleration sensor A1 was attached to a test object corresponding to the measurement object 10a in the simulation process. The acceleration sensor A1 was attached to the top surface (top surface of the cap) of the packaging container 16a, which is the test object. Next, while the container 12 was placed on the vibration table 35 of the vibration test device 30, the vibration test device 30 was operated under the same conditions as in the simulation process, and the frequent distribution of the acceleration of the measurement object 10a was obtained. The vibration time under each condition was the same as in the simulation process. 7 shows the frequency of occurrence of acceleration of the measurement object 10a obtained in the simulation process of Example 1 and the frequency of occurrence of acceleration of the corresponding test object measured by the acceleration sensor A1 of Reference Example 1. The latter Reference Example 1 is an actual measurement value of the frequency of occurrence of acceleration.

[0059] The vibration test device 30 used was a vibration test machine (model "BF-50UT" manufactured by IDEXX Corporation). The simulation process was carried out using the MotionSolve analysis software of Hyper Works manufactured by Altair Corporation. The acceleration sensor used was an 8-channel small wireless motion recorder (model "MVP-RF8-HC" manufactured by Microstone Corporation). In the vibration test of this vibration test evaluation I, the vertical acceleration was used as the measurement value of the acceleration sensor.

[0060] [Vibration test evaluation II] Regarding accumulated fatigue based on the relative acceleration of multiple measurement objects, tests were conducted by operating an actual vibration test device under the vibration conditions obtained in the simulation process, and the reproducibility of damage caused to the test objects was evaluated.

[0061] Example 2 As in Example 1, the container 12 shown in FIG. 2 was modeled, and among the rows of three packaging containers 16 arranged in the width direction Y, one of the two rows in the center of the longitudinal direction X, a packaging container 16a in the center of the width direction Y, and a packaging container 16b adjacent to the packaging container 16a and the peripheral wall of the container 12 in the width direction Y, were set as the measurement objects 10a, 10b. Also, as in Example 1, a vibration table 35 was modeled. Next, a simulation process was performed for the modeled container 12 placed on the modeled vibration table 35. In this simulation process, the accumulated fatigue based on the relative acceleration of the measurement objects 10a, 10b when vibrated by the vibration test device 30 under the conditions in Table 1 below was calculated as a value per unit time, and further, the vibration time (vibration condition) at which the accumulated fatigue becomes 3,000,000 (G^2) was derived. In other words, the target accumulated fatigue was set to 3,000,000 (G^2). In the simulation process, the difference in vertical acceleration between the multiple measurement objects 10a, 10b was taken as the relative acceleration.

[0062] Comparative Example 1 Instead of the accumulated fatigue based on the relative acceleration of the multiple packaging containers 16a, 16b, the accumulated fatigue based on the acceleration of one packaging container 16a in the housing 12 was adopted, and the vibration time at which the accumulated fatigue reached 3,000,000 (G^2) was derived. Except for this point, the same simulation process as in Example 2 was performed. The vibration time was derived for each of the conditions shown in Table 1 below. The vertical acceleration was adopted as the acceleration.

[0063] For each waveform and frequency shown in Table 1 below, a vibration test was actually carried out using the vibration time derived in Example 2 and Comparative Example 1. Such a vibration test corresponds to the above-mentioned vibration application step. An actual object having the same configuration as the modeled container 12 (cardboard box 17 and packaging container) was prepared, and a vibration test was performed using the same vibration test device 30 as in the vibration test evaluation I. After the vibration test, damages occurring in the test object (packaging container) in the container 12 were visually confirmed, and the number of such damages was counted. The damages occurring in the packaging container were holes in the label covering the outer surface of the packaging container. The packaging containers confirmed to have damage in Comparative Example 1 are packaging containers with the same arrangement as the measurement objects 10a and 10b in Example 2. Table 1 below shows the number of damages that occurred to the packaging containers.

[0064] [Reference example 2] As Reference Example 2, a transport test was conducted in which a container 12 having the same configuration as in Example 2 was actually transported over land. In the transport test, the accumulated fatigue based on the relative acceleration of two packaging containers 16a, 16b corresponding to Example 2 was 3,000,000 (G^2), and the accumulated fatigue based on the acceleration of one packaging container 16a corresponding to Comparative Example 1 was 3,000,000 (G^2). These accumulated fatigue values ​​were based on the relative acceleration or acceleration measured by attaching an acceleration sensor to the top surface (top surface of the cap) of the packaging containers 16a, 16b. The same acceleration sensor was used as in Vibration Test Evaluation I.

[0065] [Table 1]

[0066] As is clear from the graph shown in Fig. 7, the frequency of acceleration of the measurement object 10a output by the simulation using multibody dynamics was close to the frequency of acceleration of the measurement object 10a measured by the acceleration sensor. This result shows that the vibration (acceleration) from an actual vibration test can be reproduced by the simulation using multibody dynamics.

[0067] Based on the S-N curve described above, theoretically, if the accumulated fatigue applied to the measurement object in the vibration test is equivalent to the accumulated fatigue during transportation, the damage caused by the vibration during transportation can be reproduced. In addition, theoretically, if the accumulated fatigue is equivalent, the amount of damage caused between different vibration conditions will be about the same, and the amount of damage is less likely to vary between each vibration condition. However, in the vibration test of Comparative Example 1 in Vibration Test Evaluation II, the number of damages varied greatly depending on the vibration conditions (Table 1). These results show that if the accumulated fatigue is based on the acceleration of the packaging container 16 in the container 12, the reproducibility of damage caused by vibrations in the container 12 is low. On the other hand, as is clear from the results in Table 1, in the vibration test of Example 2, the variation in the number of damages was smaller than in Comparative Example 1, even when the vibration conditions were changed as shown in Table 1. Furthermore, in the vibration test of Example 2, the number of damages was closer to the value in Reference Example 2, which is an actual transportation test, than in Comparative Example 1. That is, it was shown that by basing the accumulated fatigue on the relative acceleration of a plurality of measurement objects (packaging containers 16a, 16b), damage caused by vibrations within the container 12 can be reproduced with high reproducibility. Therefore, it was demonstrated that the vibration test method of the present invention has a high reproducibility of vibration during the transportation process of the container 12, and the vibration test can be easily carried out. [Explanation of symbols]

[0068] 10a, 10b Measurement object 11 Goods 12 Containment Unit 16a,16b Packaging container 17 Cardboard Box 18 Means of transportation 19 Simulation Device 30 Vibration Test Equipment 31 Vibration generating unit 35 Shaking Table A1, A2 Acceleration Sensor X Longitudinal direction Y Width direction Z height direction

Claims

1. The method includes a simulation step and a vibration application step of applying vibration to a container in which a plurality of items are contained, using a vibration test device; the simulation step is a step of deriving vibration conditions of the vibration testing apparatus by simulation based on accumulated fatigue, The accumulated fatigue is calculated based on a relative acceleration that is an acceleration difference between a plurality of measurement objects in the container, the vibration conditions are conditions under which the accumulated fatigue caused by the vibration by the vibration test device is equivalent to the accumulated fatigue based on the relative acceleration measured while a container containing a plurality of articles is in a transport state, The vibration testing method, wherein the vibration application step is a step of applying vibration to the housing under the vibration conditions using the vibration testing device.

2. 2. The vibration testing method according to claim 1, wherein the simulation step calculates a vibration time during which the accumulated fatigue is equivalent between the vibration by the vibration testing device and the vibration under the transportation state, based on the accumulated fatigue per unit time of the vibration by the vibration testing device.

3. 3. The vibration testing method according to claim 1, wherein the plurality of measurement objects are objects housed in the housing so as to be able to come into contact with each other.

4. 3. The vibration testing method according to claim 1, wherein the plurality of measurement objects are items that are most likely to be damaged by the vibrations in the container.

5. 3. The vibration testing method according to claim 1, wherein the container is a cardboard box.

6. 3. The vibration testing method according to claim 1, wherein the simulation is performed using multibody dynamics.

7. A simulation device for deriving vibration conditions for a vibration test device, comprising: The vibration test apparatus uses a container that contains a plurality of items as a vibration target, The simulation device derives the vibration condition based on accumulated fatigue, The accumulated fatigue is calculated based on a relative acceleration that is an acceleration difference between a plurality of measurement objects in the container, A simulation device, wherein the vibration conditions are conditions under which the accumulated fatigue caused by the vibration test device is equivalent to the accumulated fatigue based on the relative acceleration measured when a container containing multiple items is in a transport state.

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